Art of making starch pebbles.



action of heat and pressure UNITED s'rA'rEs PATENT OFFICE.

ALEXANDER P. ANDERSON, OF CHICAGO, ILLINOIS.

ART OF MAKING STARCH PEBBLES.

To all whom it may concern Be it known that l", ALEXANDER P. ANDER- sox, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in the Art of- Making Starch Pebbles, of which the following is a full. clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates to an improvement in the art of treating and drying starches of all kinds and has for its object a method oi producing what I term pebbled-starch,- that is, starch in lumps of nodular or pebble-like form.

Broadly considered, my process consists in subjecting wet orgreen starch to the joint below that oi atmospheric to dry the starch down to the desired degree of moisture, and then heating the starch under pressure above atmospheric until all of the starch has been formed into nodular or pebble-like lumps having the characteristics of the product claimed and described in my co-pending application Serial No. 332,804, filed August 31, 1906.

A preferred form of apparatus for carrying out the above process is fully disclosed in my co-pending application rial No. 397,324, filed Oct. 14, 1907.

In the drawing accompanying this specification is illustrated a longitudinal sectional view of a suitable form of cooker, showing the interior construction of the same, as well as the connections for passing a heating or cooling fluid through the cooker-jacket.

The drum or cylinder (conveniently termed the cooker) comprises a pair of end heads 1 and 2,' preferably of heavy cast metal, to which is secured the outer cylindrical section 3 by means of rivets 4. The section 3 and the end heads 1 and 2 constitute the outer shell. The end head 1 is providedwith a hub 5, while the end head 2 is provided with a similar hub 6. The inner ends of these hubs have peripheral flanges or' shoulders 7 and 8, to which-are riveted the end members 9 and 10, respectively. To these end members is secured the inner cylindrical section 11 spaced from the outer Specification of Letters Yatent. Application filed October 14, 1907. Serial No. 397,325.

Patented Aug. 20, 1912.

section by stay-bolts 12. The section 11 and 9 and 10 constitute the in-' its end members ner shell. There is thusformed a space or jacket 13 which surrounds the inner shell of the cooker. The inner shell has attached thereto upon its outer surface a series of ribs or strips 14 to which are secured the cutter or stirrer-pipes 1'5 to communicate with the jacket. it. will; he noticed that the free ends of these pipes are closed, so that. any heating or cooling fluid admitted into the acket. will enter said pipes without passing therethrough. These pipes may be flattened in a plane transverse to the longitudinal axis of the cooker for the purpose of cutting or breaking large lumps of the material that may be rolled against said flattened edges during the rotation of the cooker. course. the configuration of these pipes may be varied at will: ordinary round pipes may be used, in which case they might do little or no cutting, but they would stir the material during rotation of the cooker just as eiiectively as the flattened pipes. The number of these pipes in a row, as well as the number of rows, is purely a matter of choice. I p

The cooker is rotatably supported by the hubs 5 and 6 in suitable bearing-blocks 17 and 18 mounted on standards 19 and 20. Passing longitudinally through the cooker is a stationary central pipe 21 which rests snugly in bores 22 and 23 in the hubs 5 and .6, without interfering with the free rotation of the hubs. To the central pipe 21 within the cooker is attached a series of pipes 24 which I call the breaker-pipes. These breaker-pipes are, like the stirrerpipes 1.), closed at their free ends and may be of any suitable construction,-such as cylindrical throughout their entire length.

Suitable clamps 26 may be employed for rigidly securing the arts of which clamps the pipes are screwed to communicate with the interior of the central ipe. In this way any heating or cooling fluid admitted into the said central pipe will enter the breaker-pipes without passing therethrough. A second pipe 27 is concentrically arranged within the central pipe 21, being fastened thereto so as to rotate therewith, and is sufficiently smaller in diameter to leave a space 28 between the pipes. Combreaker-pipes to the .central pipe, into the upper lQO inunicating with the interior of the pipe 27 'are the exhaust pipes 28, rigidly secured in position on the central pipe 21 in any preerred way. These exhaust pipes are open at their outer ends to establish connection between the interior of the cooker and the interior of the pipe 27. The inner end of the 'pipe 27 is closed beyond the last exhaust-pipe, as indicated at 27, while the other end is adapted to be connected to a vacuum and condensing pump, whereby the interior of the cooker may be exhausted to the desired degree of vacuum. It will bev noticed that the pipes 28 are set back at an angle relativeto the breaker-pipes 24. The object of this angular displacement of the pipes 24 and 28 on thecentra-l pipe 21 is 'to keep the free ends of the pipes 28 clear of the material under treatment when the breaker pipes 24 are turned down into the material in a direction toward the observer,

for breaking up any masses that are too' the casting 31,. said man-hole being in alinement with the opening 32 in the inner shell. An effective way of securing the casting to the cooker is,to rivet or bolt the same to the shells in the space or jacket therebetween, In the instance shown the lid 33 is hollow as indicated at 34,-that is to say, it is pro vided with a passage whereby a suitable heating or cooling fluid may be admitted into the lid for the purpose of heating or cooling the same.( as the case may be). The lid is pivotally mounted on the cooker and is held in closed or sealed position by a central member 35 adjustably carried (as, by screw-threading) in the" cross-bar 36. A hand-wheel 37 permits ready adjustment of the member 35 either for moving it toward the lid to seal the same, or for raising it out of engagement with the lid to permit opening of the same. The cross-bar 36 is pivoted at one end 38 to the upright memer 39 screwed into the casting 31. The other end 40 of the cross-bar 36 is slotted to engage the upright member 41 likewise screwed into the casting.

When it is desired to open the lid it is only necessary to raise the central member 37 out of engagement with the lid,- whereupon the cross-bar 36 may be swung aside on its pivot out of the path of the lid. By connecting the pipes 42 and 43 (which communicate with opposite sides of the jacket) with the passage in the lid, some of the heating or cooling fluid may be by-passed fluid-supply, such as'steam. The radial opening 47, into which this pipe is secured v in the stuffing-box, communicates with said steam-space. -Although the pipe 46 and its connections might be suflicient to' prevent rotation of the stuffing-box, I positively forestall any such possible rotation by connecting the flange 48 on the stufiing-box with the standard 20 by means of a brace or bracket 49. The packings 50 and 51 are ield in place by the glands 52 and 53, respectively, secured to the stufiing-box. The packing 54 at the extreme end of the hub 6 is held in place by the gland 55 secured to the hub. The radial passages 56 in the hub are in alinement with the space 45 so as to communicate therewith. At their inner ends these radial passages communicate with the longitudinal openings 57 in the hub. These longitudinal openings in turn connect with the radial passages 58 formed in that portion of the end head 2 which projects into the jacket. I

The above described arrangement at the right of the figure for the admission of a suitable heating or cooling fluid through the hub 6 into the jacket 13, is substantially duplicated at the left of the figure to permit the exit of the heating or cooling fluid from the jacket through the hub For this reason I deem it quite unnecessary and superfluous to reiterate in detail the said arrangement at the left of the figure, whereby the heating or coo-ling fluid is allowed to escape from the jacket. All that need be said with reference to the description of said arrangement at the left of the figure is that the parts numbered 44 to 58 inclusive, as set forth in the immediately preceding paragraph, are for convenience shown in duplicate at the left of the figure and numbered, respectively, 44 to 58 inclusive. I

Having thus described the structure 0 the cookertogether with the arrangement for passing a heating or cooling fluid through the jacket I shall now direct attention to the operation of the device. A suiiicient amount of the material desired for treatment is put into the cooker, whereupon the latter is sealed air-tight. The cooker is then set in rotation by connecting it with a source of power through the gear-wheel 59 rigidly secured to one of the twins. same time a heating fluid, such as charm, is

At the v turned into the jacket, entering hub 6 through pipe 46, and passing out of the jacket through hub into the drain or return pipe 46 The steam is also fed into the central pipe 21 from the right through I pipes 24, it will be apparent that the steam in the jacket enters the stirrer-pipes to heat the same uniformly with the entire inner surface of the'cooker, and that the steam passing through the central pipe 21 enters the breaker-pipes whereby the same become heated uniformly with the stirrer-pipes and the inner surface of the cooker.

During the rotation of the cooker the material is continually rolled and tumbled about, the presence of the stirrer-pipes 15 increasing the agitation of the material. In case it is desired to positively break up large lumps, the central pipe 21 is rotated in a direction toward the observer. Such rotation may be effected by a lever of some kind clamped to the central pipe. Although I haveshown the stirrer-pipes 15 in pairs, with the breaker-pipes arranged to enter the space between each pair of stirrer-pipes, any desired arrangement of the two sets of pipes may be employed. Therefore, with the breaker-pipes turned into the tumbling material, any masses or lumps too large to pass in between the movable stirrer-pipes and the stationary breaker-pipes will be crushed or broken. By this means the material is broken up Into pieces more or less uniform in size. Should it be desired to subject the interior of the cookerv to pressure below atmospheric, it is only necessary to open communication between pipe 27 and a vacuum pump.

Having thus briefly described one form of, suitable apparatus for accomplishing the various steps of my process, I shall now proceed to set forth in detail the preferred manner of carrying my process into effect. A sufficient quantity of wet or green starch of known moisture-percentage and in clean condition is put into the cooker to fill the same from one-third to one-half. The treating-chamber is now sealed air-tight, and the rotation ofthe cooker begun. A steampressure'of about 1 to 15 ounds per square inch is turned onto the jac et. At the same time the vacuum and condensing pump is started and kept at about 27 inches of mercury until enou h water has been drawn off from the starc (as shown by wei hing or measuring it) to bring the totaI moisture of the starch down to about 25%. During this treatment the starch forms into worn, pebble-like lumps of varying sizes (as fullv exlained in my copen ingapplication Serial 0. 332,804, above mentioned); but, with the breaker-pipes turned down so as to tallow the stirrer-pipes to break up anyv lumps that'are too large to pass in between said pipes, the lamps formed are sufliciently uniform in size to harden and finish. Mixed with these pebble-like. ieces will .be some powder from lumps w ich are dried too much and thus crumble. The vacuum-pressure is now. decreased slowly (as, for example, by running the pump at a lower speed) or, it may be stopped altogether. In either case the starch becomes subjected to a greater heat, its temperature soon reaching the neighborhood of degrees C., or more,

due to the surrounding vapor which is at about the same temperature as the starch, the latter at this pointgelatinizing to a slightextent.

It is to be understood that when I mention a temperature of 70 de ees (3., or thereabout, I mention it for t e sake of illustration only,-that is to say, the temperature of the starch is raised to about 70 C.

provided the gelatinization-point of the particular kind of starch under treatment hegins at about 70 C. Some other kind of starch might have a different point of gelat inization, in which case the temperature would be regulated accordingly. The particular detail, therefore, to be borne in mind here is that the temperature of the starch should be raised onlyutar enough to effect slight gelatinization of the starch. Manifestl the temperature of the starch depen s u on and is determined by the pressure wit in the cooker, whether said pressure is above or below atmospheric. This slight gelatinization causes the starch to gather up all of the loose powder, and as soon as-gage-pressure has formed within the cooker all of the starch will be formed into a pebbled lump-condition. The pressure wit in the cooker is now slowly reduced, as by being blown off to zero, whereupon the starch-pebbles are taken out. The starch thus produced will be found to be about air-dry, and possesses the properties and characteristics of the product claimed in my 00- ending application identified in the sec- 0nd paragraph of this specification.

Certain of the details accompanying the steps as above given might be preferably .varied in instances like the following: A

sufiicient quantity of wet starch containing about 50% of total moisture is put into the treating-chamber to till the same from onethird to one-half. The treating-chamber bein sealed air-tight, rotation of the cooker is gun,-and a vacuum of about 27 inches.

of mercur is created within the chamber. while at t esame time a steam-pressure of about [to 15 pounds is fed into the jacket. It will be understood that, by thus providing within the cookera pressure below atmospheric, I accomplish a two-fold purpose,-to wit, the rapid drying of the starch down to the desired degree of moisture, and the maintenance of the temperature of the starch below the point of gelatinization. This drying of the starch at low temperature is continued until its total moisture reaches about 27%, readily determined by measuring or weighing the water drawn oif. During the drying great care should be exercised not to allow the temperature of the starch to reach the gelatinization-point in order not to cook or gelatinize it to any extent whatsoever. The cooker is now stopped and the starch taken out to be freed from all impurities (such as gluten lumps, and the like) by crushing or grinding, if necessary, and then running through a fine sieve or coarse bolting cloth. Any other customary or preferred method of taking the dirt om of the starch may be resorted to. The cleaned starch is now put back into the same machine or into another machine of the same kind,it being understood that one or more machines may be used for the drying of the starch, while others may be used exclusively for the lumping or pebbling of the same. The cooker is then sealed and its rotation begun. At the same time a jacket steampressure of about 20 to 60 pounds is turned 011.

During the rotation of the cooker the starch isheated, its temperature in about half an hour reaching the neighborhood of 100 degrees C. Soon thereafter steam and pressure begin to form from the moisture in the starch. Due to the surrounding steam and moisture, the starch begins to gelatinize to a slight degree. The starch-granules begin to stick together to form nuclei or centers which in rolling grow in size by the aecre tion of other granules and loose starch powder. This is true also of minute starchmasses which have formed during the tumbling of the starch. In a short time, the whole starchy mass within becomes converted into innumerable which soon gather up all the loose powder. The heating and tumbling of the starchlumps thus formed is continued for a sufficient period during which they become worn, as well as acquire a more or less smooth and hardened periphery which prevents their powdering or crumbling. It has been found that a pressure of from 20 to-etO pounds per square inch withinthe cooker is about right. The operation is now brought to a completion by blowing this pressure off to zero; and, should it be found that the starch-pebbles are not about air-dry, they can readily be brought down to about 14% total moisture by reducing the pressure within the cooker below atmospheric for about fifteen minutes, during which time the starch dries rapidly, as well as cools down to a temperature at which it can be graded for packing or storage.

sticky centers Of course, it is apparent that the intermediate step of cleaning in the last example cited, is not necessary when clean starch is used in the very beginning. Neither is it esconsists in heating, wet starch in a partial vacuum to dry the starch down to'the desired degree of moisture, the temperature of the starch being kept below the point of gelatinization, and then heating the starch to a temperature suflicient to slightly gelatinize it and tumbling the same until substantially all of the material has formed into pebblelike lumps.

2. The process of pebbling starch which consists in heating wet starch ina partial vacuum to dry the starch down to the desired dmree of moisture, the temperature of the starch being kept below the point of gelatinization, then tumbling the starch in a closed receptacle and heating the same until sufficient pressure has formed therein to effect partial gelatinization of the starch, and continuing the heating and tumbling until substantially all of the material has formed into pebble-like lumps, and then slowly reducing the pressure.

3. The process of pebbling starch which consists in heating wet starch in a partial vacuum to dry the starch down to the desired degree of moisture, the temperature of the starch being kept below the point of gelatinization, and then heating the cleaned starch in a closed receptacle to the degree necessary to slightly gelatinize it; and tumbling the same until substantially all of the material has formed into pebble-like lumps. 4. The process of pebbling starch which consists in heating wet starch in a partial vacuum .to dry the starch down to the desired degree of moisture, the temperature of the starch being kept below the point of gelatinization, then cleaning the starch thus dried, and then heating the starch in a closed receptacle to the degree necessary to slightly gelatinize it, meanwhile tumbli the same, then continuing the heating an tumbling until substantially all of the material has formed into pebble-like lumps, and then slowly reducing the pressure.

5. The process of pebbling starch which Consistsin heating wet starch in a partial vacuum to dry the starch down to the desired degree of moisture, the temperature of the starch being kept below the point of ge latinization, then cleaning the starch thus dried, then heating and tumbling the cleaned starch in a closed receptacle until a pressure of about 20 to 40 pounds per square In witness whereof, I have hereunto sublnch has developed therein, whereby the scribed my name in the presence of two witstarch becomes slightly gelatinized, and connesses.

tinuingthe tumbling action until substan- ALEXANDER P. ANDERSON. 5 tially all of the material has formed into Witnesses:

pebble-like lumps, and then slowly reducing J. JAY SMITH, the pressure. LOUISE RAND BASCOM. 

